I have noticed that if nodes are named with either a "+" or a "-" character at the start, the simulator fails to run correctly, e.g. two nodes named "-5V" will not be connected together

I would think this would be a basic feature to support for node names (e.g. for the negative supply of an op-amp. Currently I am having to use a node name like "5V-" which is a tad ugly and unconventional.